FESTER: A propagation experiment, overview and first results

A long term field trial called FESTER (First European South African Transmission Experiment) has been conducted by an international collaboration of research organizations during the course of almost one year at False Bay, South Africa. Main objectives of the experiment are a better insight into atmospherical effects on propagation of optical...

Developments in modelling of thermal radiation from pool and jet fires

In the past decades, the standard approach in the modelling of consequences of pool and jet fires would be to describe these fires as tilted cylindrical shaped radiating flame surfaces, having a specific SEP (Surface Emissive Power). Some fine tuning on pool fires has been done by Rew and Hulbert in the late nineties to divide the flame in a...

Wat als de zon het licht uitdoet

Voor het leven op aarde speelt het aardmagnetisch veld een cruciale rol om ons tegen deze stroom geladen deeltjes te beschermen. In extreme situaties merken we de effecten van ruimteweer zelfs op aarde. Inzicht in het ruimteweer is daarom belangrijk om tijdig te kunnen beoordelen of zonneactiviteit invloed kan uitoefenen op de aarde en de...

Reconventionalization following antibiotic decontamination in man and animals

Antibiotic decontamination of the digestive tract can suppress or eliminate all microorganisms in this tract that are sensitive to the antibiotics used for decontamination. Experimental work in animals has indicated that colonization resistance (CR) decreases to extremely low values during decontamination as a result of the suppression of the...

Enhancement by drugs of metastatic lung nodule formation after intravenous tumour cell injection

In studies on a model of induced pulmonary metastasis in mice a tumour host system was analysed which was not affected by immunogenicity of the tumour for the host; neither intensive immunosuppression nor immunization caused a significant change in the quantity of pulmonary metastatic nodules. In contrast the application of cytostatic drugs and...

Radiosensitization of biologically active DNA in cellular extracts by oxygen. Evidence that the presence of SH compounds is not required

The radiosensitization by oxygen of biologically active bacteriophage DNA in bacterial extracts was studied. The oxygen effect in such a system appeared not to be due or only to a minor extent to the presence of endogenous sulphydryl compounds. The components in a cell extract which enable oxygen and other sensitizers to sensitize DNA could not...

Influence of the radiosensitizers paranitroacetophenone and triacetoneamine N oxyl on the effects of ionizing radiation on DNA

Paranitroacetophenone (PNAP) and triacetoneamine N oxyl (TAN), which sensitize anoxic cells to ionizing radiation, do not increase the radiosensitivity of bacteriophage DNA irradiated in the dry state, showing that the 'direct action model' of sensitization does not hold in this experimental set up. PNAP and TAN added within 1.5 msec after...

Repair of X-ray damage in DNA of cultivated cells from patients having xeroderma pigmentosum

Repair replication and rejoining of single-strand breaks after X-irradiation in human-skin fibroblasts from normal donors and several patients with xeroderma pigmentosum have been compared. The xeroderma strains showed different levels of repair replication following UV exposure. Repair replication and rejoining of breaks, which are considered...

The regulation of cell proliferation and differentiation in intestinal epithelium. II. A quantitative histochemical and autoradiographic study after low doses of X-irradiation

To investigate the biochemical mechanisms involved in the regulation of cell proliferation and differentiation the intestinal epithelium has been chosen because of the regular distribution of proliferative-, non-dividing maturing- and functional cells along the crypt and villus. The effect of low doses of irradiation (50-400 R) which selectively...